Apparatus and method for producing a bent laminate

Abstract

An apparatus and method is disclosed for the bending and pressing of laminations into 2-dimensional or 3-dimensional curves. The apparatus includes a pair of spaced apart rotatable clamps for the clamping of the laminations at spaced apart locations. At least one of the clamps is movable towards the other clamp. Counterclockwise rotation of the clamps bends the laminations held by the clamps. A clamping force of at least one of the clamps is controllable so that the laminations may be bent while a mutual sliding movement of the laminations in at least one clamp is permitted. The laminations are bent to a radius larger than a desired radius. At this point, the clamping pressure is increased to prevent the mutual sliding movement so that upon further bending of the laminations, the outer laminations are pressed against the inner laminations at a substantially evenly distributed force along the bent section of the laminations. The apparatus is easily adaptable to produce different shapes and sizes of 2- and 3- dimensional curvatures and permits the fast and economical bending and compression of a workpiece having individual layers.

We claim: 
     
       1. An apparatus for producing a bent laminate of at least two continuous laminations of a flexible material, comprising: first and second clamping means for clamping together the laminations at spaced apart clamping locations;   means for rotatably supporting the clamping means, the first and second clamping means being respectively rotatable around first and second axes of rotation, at least one of the clamping means being movably supported for movement towards and from the other clamping means;   means for selectively rotating at least one of the clamping means to permit bending of laminations held by the clamping means; and   means for selectively preventing mutual sliding movement of the laminations, the axes of rotation being positioned so that the bending of the laminations when the mutual sliding movement is prevented, forces the laminations against each other at a substantially evenly distributed force between the clamping locations, the laminations being of sufficient strength to withstand the force created.   
     
     
       2. An apparatus as defined in claim 1, further comprising: a flexible pressure band, the first and second clamping means permitting clamping of the laminations to the pressure band at spaced apart locations,   rotation of the clamping means permitting bending of the laminations clamped to the pressure band; and   the means for selectively preventing a mutual sliding movement preventing a mutual sliding movement of the laminations and the pressure band, the axes of rotation being positioned so that bending of the laminations and the pressure plate while the mutual sliding movement is prevented forces the pressure plate against the laminations at a substantially evenly distributed force between the clamping locations.   
     
     
       3. An apparatus as defined in claim 2, wherein a pair of pressure bands is provided for clamping layers of a laminate therebetween, and the means for selectively preventing the sliding movement prevents the mutual sliding movement of the pressure bands, so that a bending of the laminations and the pressure plates, forces the pressure plates against each other, thereby compressing the laminations. 
     
     
       4. An apparatus as defined in claims 1, 2 or 3, wherein the means for rotatably supporting the clamping means is a frame having first and second horizontal rotatable carriers supporting the first and second clamping means respectively. 
     
     
       5. An apparatus as defined in claim 4, wherein at least one of the first and second carriers is slidably mounted to the frame for movement to and from the other of the first and second carriers. 
     
     
       6. An apparatus as defined in claim 5, wherein the means for selectively rotating at least one clamping means includes for each clamping means to be rotated a rotatable shaft, means for rotating the shaft and a lever rigidly affixed with its respective ends to the shaft and to one of the first and second carriers so that rotation of the shaft rotates the clamping means supported by the one carrier around its axis of rotation. 
     
     
       7. An apparatus as defined in claim 6, wherein the means for rotating the shaft is an electric motor providing a torque, the electric motor being connected to the shaft through a transmission for increasing the torque. 
     
     
       8. An apparatus as defined in claim 1, wherein the means for selectively preventing mutual sliding movement of the laminations controls a clamping force of at least one of the first and second clamping means to selectively clamp the layers at a low clamping force permitting mutual sliding movement of the laminations and at a high clamping force preventing the mutual sliding movement of the laminations. 
     
     
       9. An apparatus as defined in claim 8, wherein the clamping force of one of the first and second clamping means is controlled to prevent the mutual sliding movement of the laminations and the clamping force of the other clamping means is controlled to selectively clamp the laminations at one of the high and low clamping force. 
     
     
       10. An apparatus as defined in claims 8 or 9, wherein the first and second clamping means are provided with means for preventing one of an innermost and an outermost of the laminations from sliding through the clamping means at both the low clamping force and the high clamping force. 
     
     
       11. An apparatus as defined in claims 2 or 3, wherein the means for selectively rotating at least one clamping means includes for each clamping means to be rotated a rotatable shaft, means for rotating the shaft and a lever rigidly affixed with its respective ends to the shaft and to one of the first and second carriers so that rotation of the shaft rotates clamping means supported by the one carrier around its axis of rotation. 
     
     
       12. An apparatus as defined in claim 11, wherein the means for selectively preventing mutual sliding movement of the laminations and the pressure bands controls a clamping force of at least one of the first and second clamping means to selectively clamp the laminations and the pressure bands at a low clamping force permitting mutual sliding movement of the laminations and the pressure bands and a high clamping force preventing the mutual sliding movement. 
     
     
       13. An apparatus as defined in claim 11, wherein the clamping force of one of the first and second clamping means is controlled to prevent the mutual sliding movement and the clamping force of the other clamping means is controlled to selectively clamp the laminations and the pressure bands at the high and the low clamping force. 
     
     
       14. An apparatus as defined in claim 12, wherein the first and second clamping means are provided with means for preventing one pressure band from sliding through the clamping means at both the high and the low clamping force. 
     
     
       15. An apparatus as defined in claim 10, wherein the means for preventing one lamination from sliding through the clamping means are incorporated into the clamping means and forced into engagement with the one lamination. 
     
     
       16. An apparatus as defined in claim 10, wherein the means for preventing one pressure band from sliding through the clamping means are spurs incorporated into the clamping means and forced into engagement with the one pressure band. 
     
     
       17. An apparatus as defined in claims 1, 2 or 3, wherein at least one of the two clamping means is movable parallel to its axis of rotation. 
     
     
       18. An apparatus as defined in claim 8, wherein at least one of the two clamping means is movable parallel to its axis of rotation. 
     
     
       19. A method of producing a bent laminate having at least two continuous flexible laminations comprising the steps of: clamping together the laminations at spaced apart clamping locations and at a clamping force permitting mutual sliding movement of the laminations;   bending the layers between the clamping locations to a radius of curvature larger than a desired radius of curvature;   increasing the clamping force at the clamping locations to prevent the mutual sliding movement; and   further bending the layers to the desired radius of curvature so that the laminations are forced against each other at an even pressure along the curvature, the laminations being of sufficient strength to withstand the pressure created.   
     
     
       20. A method of producing a bent laminate having at least two continuous, flexible laminations, comprising the steps of: clamping the laminations to a pressure band at spaced apart clamping locations and at a clamping force permitting mutual sliding movement of the laminations and the pressure band;   bending the laminations and the pressure band between the clamping locations to a radius of curvature larger than a desired radius of curvature;   increasing the clamping force at the clamping locations to prevent the mutual sliding movement of the laminations and the pressure band; and   further bending the layers to the desired radius of curvature so that the pressure band is forced against the laminations between the clamping locations at an evenly distributed pressure force, the laminations being of sufficient strength to withstand the pressure created.   
     
     
       21. A method of producing a bent laminate having at least two flexible laminations, comprising the steps of: clamping the laminations between a pair of pressure bands at spaced apart clamping locations and at a clamping force permitting a mutual sliding movement of the pressure bands;   bending the laminations and the pressure bands between the clamping locations to a radius of curvature larger than a desired radius of curvature;   increasing the clamping force at the clamping locations to prevent the mutual sliding movement of the pressure bands; and   further bending the laminations and the pressure bands to the desired radius of curvature so that the pressure bands are forced against each other and compress the layers between the clamping locations at an evenly distributed pressure force.